How much can be measured -- and how much cannot?

There has been a lot of discussion over the years on Audiogon regarding the measurement of components and other audio products. Some people claim everything is either measurable now or will one day become measurable with more sophisticated measuring equipment. But others say there are things in high end audio that will never me measurable and that measurements are really not that important.

Here is a typical example -- a quote taken from the Stereophile forum regarding their review of the Playback Designs MPS-5:

"JA 2/17/10 Review Measurements of Playback Designs MPS-5
Posted: April 13, 2011 - 8:42am

John Atkinson's 2/17/10 review measurements of the Playback Designs MPS-5 revealed less than stellar technical performance even though Michael Fremer really liked the player. I've included JA's closing measurement remarks below followed by the manufacturer's comments.

To my knowledge there was never any followup in Stereophile regarding the manufacturers reply the MPS-5 could not be adequately measured with traditional measurement techniques.

I believe Stereophile should respond to this reply in the interests of its own measurements credibility.

Len"

How important do you think measurements are? Are the ears really the only true arbiter?